Inspection of complex parts by non-destructive technologies can be quite challenging as finding and sizing a flaw or defect heavily depends on probe positioning during inspection. In the exemplary embodiment of this invention, a nozzle weld phased array ultrasonic (PAUT) inspection is used. The exact position and number of required PAUT scan lines on particular nozzle geometry is defined by the scan plan, knowing that for weld inspection the whole weld zone must typically be completely covered by the various PAUT beams. The complex shape of the nozzle, defined by the intersection of two cylinders, makes it difficult to follow the inspection scan line to ensure correct coverage of the inspected weld as defined by the scan plan.
The conventional way of conducting PAUT nozzle inspection is manually, with or without a guide on the part. The user must be experienced as he needs to compensate for the effects of the geometry on the ultrasound signal path in order to achieve the interpretation of the scan result. Because such an inspection relies heavily on the user's experience, reproducibility and reliability is poor. Under those conditions, it is also impossible to ensure the complete part was covered and to save meaningful data as the real position of the probe is unknown to the inspection system.
A more robust way of inspecting a nozzle is to use an automated scanner, specific to the nozzle geometry, which encodes all PAUT probe movement and ensures coverage by precisely positioning the probe on the inspected part surface. Such a scanner is an expensive alternative and is not suitable for all markets. It also takes a lot of time to deploy, install and it lacks the manual versatility to better size a flaw or defect.
Either solution requires having a scan plan which is calculated depending on measured parameters of the nozzle such as radius, thickness, pipe thickness and pipe radius.
Advances in technologies now permit a probe to locate an object with very good precision without the use of a specific scanner. In the preferred embodiment, the chosen encoding unit is a 3D camera that uses two specific objectives to locate a moving target, which reflects infrared, using the stereoscopy principle. Attempts have been made to use such advanced encoder systems for the manual inspection of complex geometries such as the nozzle. While these attempts solved some of the limitations of manual inspection (such as traceability and analysis) it has not been devised as an effective tool for guiding the probe position during the inspection.
It would be desirable to have a way of using the advanced encoding unit, a 3D camera, to provide adequate feedback of the scanning path during the inspection in order to significantly increase the accuracy and efficiency manual inspection.